a. Field of Invention
The invention relates generally to manually actuated pump sprayers, and more particularly to such sprayers having means for preventing clogging of the discharge orifice due to product drying at the orifice and means for locking the plunger head for preventing plunger reciprocation.
b. Description of Related Art
Prior art pumps of the general type are known as having some type of anti-clog means such as the provision of a small projection extending into the orifice opening from outside the orifice cup. The projection is provided on a cover overlying the plunger head and shiftable relatively thereto for both sealing the orifice closed and for breaking away any accumulated dried product which may have accumulated on the outside surface of the orifice cup.
Alternatively, the discharge nozzle itself may be pivotable out of alignment from the discharge passage for protection against pollution, as well as for the prevention of dried product accumulation at the discharge orifice. In certain cases, a cover having a discharge opening may be provided for enabling discharge of product upon alignment of the opening with the discharge orifice. U.S. Pat. Nos. 5,203,841 and 5,027,982, the disclosures of which are incorporated herein by reference, are examples of such related art.
Other solutions for preventing clogging of the discharge orifice include the incorporation of an anti-clog element which confronts the discharge orifice upon rotation of the pump head to a predetermined orientation, as shown for example in U.S. Pat. No. 5,918,774, the disclosure of which is incorporated herein by reference. Yet further, as provided in U.S. Pat. No. 3,474,939, the disclosure of which is incorporated herein by reference, the plunger head may be rotated for locking in an up position whereby dispensing of product is prevented by the dual action of the plunger head being locked and the discharge orifice engaging a complementary cover.
These solutions to prevent orifice clogging are not, however, without their disadvantages. For example, extending a protrusion or the like into the orifice from the outer surface of the orifice cup for anti-clogging purposes, could over time distort the orifice and thereby adversely affect the quality of spray through the orifice. Also, the protrusion on the cover could after repeated use overshoot or undershoot the orifice in the non-use position such that the protrusion is out of axial alignment with the orifice in a non-use position thereby defeating the anti-clog feature.
The solutions which utilize a pivotable discharge nozzle have drawbacks in that the nozzle can become damaged after repeated pivoting thereof, and the presence of contaminants over time can further deteriorate the pivoting function. Lastly, the solutions which employ separate sealing elements or provide for locking of the plunger head have exemplary drawbacks in that existing designs are difficult to operate and fail to provide the requisite repeatability needed for adequate sealing of the discharge orifice for the life of the product.
It would therefore be of benefit to provide a manually actuated pump sprayer having in combination means for preventing clogging of the discharge orifice due to product drying at the orifice and means for locking the plunger head for preventing plunger reciprocation such that the anti-clogging feature functions in a repeatable and predictable manner over the life of the discharge assembly and the product being discharged. There also remains a need for a means for preventing clogging of the discharge orifice, which is robust in design, efficient to operate, simple to assemble and disassemble, and which is economically feasible to manufacture.